John kiewicz



1; KIEWICZ.

BUTTONHULE SEWING MACHINE.

APPLICATION FILED JAN. I0, I917.

1 26,667 Patented Dec. 30, 1919.

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' John Kiewicg byim/wl WkfM. AIIys.

1 iiNiTED STATES PATENT OFFICE.

JOHN KIEWICZ, 0F BOSTON, MASSACHUSETTS, ASSIGNOR TO THE REEOE BUTTON HOLE MACHINE COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MAINE.

BUTTONHOLE-SEWING MACHINE.

To all whom it may concern:

Be it known that I, JOHN KIEWIGZ, a citizen of the ,United States, residing at Boston, county of Suffolk, State of Massachusetts, have invented an Improvement in Buttonhole-Sewing Machines, of which the following description, in connection with the accompanying drawing, is a specification, like characters on the drawing representing like parts.

This invention relates to buttonhole sewing machines having both an upper and an under-thread-handhng mechanism, and it has for its object to provide a novel tensioncontrolling device for the under thread by which the tension on the under thread will be automatically applied at the beginning of the stitching operation on a buttonhole and will be automatically relieved at the end of the stitching operation on a buttonhole.

sion device showing the tension on the' sewing machine havin m In order to give an understanding of my invention, I have illustrated in the drawings a selected embodiment thereof which will now be described, after which thenovel features will be pointed out in the appended claims.

Figure 1 of the drawings shows in side view a sufficientportion of a buttonhole improvements applied thereto to ena le t e invention to be illustrated;

Fig. 2 is a front view of the tension .de-

vice;

Fig. 3 is an enlarged side view of the tenthread relieved.

Fig. 4: is a plan view of the actuating lever.

Inasmuch as the present invention relates solely to a tension device for the under thread and the means for actuating it, I have not deemed it necessary to illustrate the complete buttonhole sewing machine. I have, however, shown the portion of a frame of a sewing machine comprising the base plate 1 and overhanging arm 2 and have illustrated at 3 the under-thread-handling mechanism. The upper-thread-handling mechanism is in the form of the usual needle 4 carried by a reciprocating needle bar 5. The machine herein shown also includes the usual work-holding means in the form of a clamp plate 6 and work clamps 7 Specification of Letters Patent. Patented p go, 1919, Application filed January 10, 1917.

Serial No. 141,668.

which are pivotally mounted to move toward and from the clamp plate 6.

The sewing machine herein illustrated is of that well-known type which is so .constructed that when the machine is set in operation the work-holding means and stitch-forming mechanism first have a movement relative to each other to carry the work from buttonhole-cutting to stitching position, at which time the stitch-forming mechanism is set inoperation and the workholding means and stitch-forming mechanism then have a further relative feeding movement to feed the work as the stitching proceeds around the buttonhole, and when the buttonhole is completed, the stitchforming mechanism is brought to rest and the work-holding means and stitch-forming mechanism have a further relative movement'to restore the parts-to initial position. This relative movement may be provided for either by moving the stitch-forming mechanism relative to the work-holding means or by moving the work-holding means relative to the stitch-forming mechanism. In the device herein illustrated this relative movement is secured by a movement of the work-holding means on the base frame 1 and such movement is derived from the usual feed cam which is indicated at "8. This feed cam has a cam groove therein in which is received a roll 9 on a projection depending from an actuating slide 10, all as usual in sewing machines of this type, and this slide is connected to the clamp plate 6 by means. of a'latch connection 11. Inasmuch as this is a construction commonly found in sewing machines of this type, I do not deem it necessary to further illustrate it. I might, however, refer to United States Patent No. 1,188,942, dated June 27, 1916, as giving a better illustration of this feature.

The parts thus far described are or may be all as illustrated in said above-mentioned patent.

vAs stated above, my present invention relates to a tension device for the under thread which is so constructed that the tension is automatically applied at the beginning of the stitching operation and is automatically released at the end of the stitching operation. This tension device for the under thread is shown generally at 12, and it may be of familiar construction in that it comwhich the under thread 15 is received, and

a spring 16 acting on the friction disk 14 and yieldingly pressing the disks together. This tension device is shown as mounted on a bracket 17 which is secured to the portion 18 of the frame. This bracket is provided with a thread-guiding aperture 22 through which the under thread 15 passes from the source of supply and also with a thread guide 19 through which the thread passes as it leaves the tension device, the portion of the thread between the aperture 22 and thread guide 19 being situated between the friction disks 13 and 1 1. From the thread guide 19, the under thread 15 passes to another thread guide 20, from which the thread passes to the lower end of the hollow spindle 21 of the under-thread-handling mechanism. In machines of this type, the upper and under-threachhandling mechanisms are rotated during the stitching operation and the situation of the thread guide 20 is such that the thread will always be properly delivered to the lower end of the hollow spindle 21 in all positions of the latter.

The spring 16 constitutes automaticallyoperative means for applying tension to the under thread. For relieving the tension at the proper time, I have provided herein an L-shaped lever 23 which is pivoted at 24c to the bracket 17 and which is provided with a nose 25 that is adapted to engage a flange 26 formed on the friction disk 14: of the tension device. This lever 23 is connected by a link 27 with an actuating lever 28 that in turn is pivoted at 29 to the frame of the machine. When the tension device is operative to apply tension to the thread, the parts are in the position shown in Fig. 1, but if the lever 28 is swung downwardly into the dotted line position, Fig. 1, then the corresponding swinging movement of the lever will ope-rate to separate the friction disks, thus relieving the tension on the thread. I have herein provided means for swinging the lever 28 into the dotted line position at the end of the stitching operation and for holding it in this position until the stitching operation begins again, and while various devices might be employed for this purpose, I have herein chosen to utilize the movement of the slide 10 for this purpose.

The lever 28 is shown as provided with an extension 30 which is situated to be engaged by a portion of or projection 31 on the slide 10 as the latter moves, and the parts are so positioned relative to each other that at the end of the stitching operation, the slide 10 will be so positioned that the portion 31 thereof will be about to engage the extension 30 so that as the slide continues its movement to the right, Fig. 1, after the stitch ing operation has ceased thereby to carry the work from stitching to buttonholecutting position, the portion 31 of the slide will engage the extension 30 of the lever and swing the latter into the dotted line position, Fig. 1, thus relieving the tension on the thread. The parts will remain in this position until the machine is set in operation for stitching the next buttonhole, at which time the movement of the slide 10 to the left, Fig. 1, to carry the work from buttonhole-cutting to stitching position will remove the portion 31 of the slide from the extension 30 of the lever 28 and will allow the spring 16 to automatically apply the tension to the thread.

I claim:

1. In a buttonhole sewing machine, the combination with work-holding means, of stitch-forming mechanism including means for manipulating an upper and an under thread, a cam-actuated slide for moving the work-holding means and stitch-forming mechanism relative to each other, a tension device for the under thread, a lever adapted by its movement to actuate said tension device to release the tension on the under thread, and asecond lever connected to the first-named lever and adapted to be moved by said slide at the end of the stitching operation thereby to release said tension.

2. In a buttonhole sewing machine, the combination with a frame having a base plate and a depending portion, of workholding means movably mounted on the base plate, underthread-handling mechanism carried by said depending portion of the frame, a tension device for the under thread secured to said depending portion, a lever adapted by its movement to actuate said tension device to release the tension on the thread, a second lever connected to the firstnamed lever and adapted to be moved by the movement of the work-holding means at the end of the stitching operation thereby to relieve the tension on the under thread.

In testimony whereof I have signed my name to this specification.

JOHN KIEWICZ. 

